1. Field of the Invention
The present invention relates to an on-vehicle system, and particularly to an on-vehicle navigation system which operates a plurality of operating systems.
2. Prior Art
A technology, that in a computer system for operating a plurality of different operating systems using a single processor, a peripheral device connected to a computer is commonly used by a plurality of operating systems, is proposed, for example, in Japanese Patent Application Laid-Open No.2000-330806.
According to the technology, by allocating interrupt signals from the peripheral device to the operating systems depending on causes of the interruption, the peripheral device is commonly used by the plurality of operating systems.
As an example of the on-vehicle terminal system, a navigation system mounted on a vehicle, in general, reads map data recorded in a memory medium such as a CD-ROM, a DVD-ROM or the like as electronic information to develop the data to a graphics. Thus, the navigation system has the function of guiding the vehicle through a route to a destination by displaying the result of the generated map on a display unit.
In recent years, a communication unit such as a cellular phone or the like is connected to the navigation system to obtain information on facilities around a place at present time or a destination from an information center, or to output information on a status of the vehicle based on information from various sensors provided in the vehicle to the outside of the vehicle. Therefore, the peripheral devices such as the display unit, the communication unit, the network unit and so on are connected to the navigation system.
In the navigation system, a single operating system is generally operated. The operating system executes scheduling by controlling various kinds of resources such as a processor, a memory etc and the peripheral devices such as the display unit, the communication unit etc so as to be efficiently operated.
There are various kinds of operating system. Operating systems having various kinds of characteristics have been developed according to the uses. That is, an operating system suitable for batch processing, an operating system suitable for user interface and an operating system suitable for real time processing have been developed.
The navigation system is one kind of computer systems having a processor. Accordingly, the navigation system can commonly use the peripheral devices by operating a plurality of operating system. Therefore, operation of the plurality of operating systems by the navigation system is considered to be useful because processing of the operating part, the communication part can be executed using an OS for office work which is good in user interface and abundant in general applications, and because processing of interruption from the sensors for position detection or the like can be executed using an OS for real-time processing which is high in reliability and speedy in response.